Creative decompression

[Dangerious P. Cats]

How could decompressing sections of a spaceship be best utilised for defence against boarding actions? What kind of strategies would be involved in doing so, also what skills would you use? Also how might invaders defend against malicious decompression?

Also could decompression be used against other kinds of attack?

[Snoman314]

In most settings, everyone involved in spacehip combat would be in pressure suits as soon as action stations are sounded, surely. It would make even less sense for boarders not to be in pressure suits. So any effect is going to be minimal.
Also consider that any ship that can have sections reliably decompressed at will, is a potentially big safety hazard. The method used to achieve this ought to be secure from accidental and enemy activation. But surely it would be safer to design a ship that cannot be easily decompressed.
That said, when air decompresses rapidly, the moisture condenses out rapidly as well, making observation difficult for a moment or two. The obscuration, potentially combined with the force of lots of rapidly moving air (depending on how decompression is achieved) could potentially cause those in the affected compartment a moments distraction that might be used by personnel preparing to counterattack.
If there were a bunch of boarders in a pressurised compartment standing near an airlock that you can say, blow the explosive emergency release bolts on inner and outer door, then I'm sure they'd be off balance when you blew the internal hatch and came pouring through. You could perhaps use the surprise rules from B393.

here's a video of decompression fog forming: http://www.youtube.com/watch?v=CS9UH8Pg_aY

[Trachmyr]

In every space campaign I've run, uniforms are in fact Mechanical Counterpressure Suits, and evryone usually carries a small inflatable helmet with a 3 minute + scrubber air supply in a caro pocket.

Most enemy boarders should have pressure suits, and decompressing compartments is typical boarding procedure... it helps isolate parts of the ship.

However, most ships in my games are designed to decompress (though not so rapidly as to be considered explosive) for fire suppression.

[vsh]

That depends mostly on style of the game. In sci-fi decompression is a common hazard during boarding to the point of standart operation procedure. Boarding team will be in spacesuits, so if boarded ship's team is not prepared that's attackers who get the advantage.
But in swashbuckling space opera or space fantasy, like Star Wars air jets will throw attackers around and so on.

[shawnhcorey]

Neither side would want decompression, it wastes air. It's the same as the days of the tall ships. It was easy enough to set the sails on fire but no-one did because whoever won would want to use them later.

And all sections of a spaceship would have airlocks between them for the simple reason that if it didn't, you couldn't get through. Consider a small hatch, say 2 ft by 3 ft. That's 864 sq. in. If there was a pressure difference of 1 lb per sq. in. then there would be 864 lbs of force holding the hatch close. If the spaceship had a full atmosphere of 14 lbs. per sq. in. there would 6.048 tons of force holding it close.

[Purple Haze]

Originally Posted by shawnhcorey

It's the same as the days of the tall ships. It was easy enough to set the sails on fire but no-one did because whoever won would want to use them later.

This is all kinds of wrong.

In ship versus ship combat incendiary attacks were never used because they were more dangerous to the firing ship than the target. Very common for shore batteries doing port defense though.

Attacking the rigging was very common, often the first phase of the battle. Both to remove the enemies tactical mobility and because fallen sails and spars could make firing the cannons impossible until they had been cleared. As a result it was almost universal to take down most of one's own sails before combat. (Battle of Trafalgar a notable exception Nelson had the British fight that one under full sail.)

Sails and rigging wore out at a rapid pace. A ship would normally carry enough store to rerig the ship several times. As long as the masts were still standing, getting sailing again would be a matter of hours.

[DemiBenson]

Originally Posted by shawnhcorey

Neither side would want decompression, it wastes air. It's the same as the days of the tall ships. It was easy enough to set the sails on fire but no-one did because whoever won would want to use them later.

And all sections of a spaceship would have airlocks between them for the simple reason that if it didn't, you couldn't get through. Consider a small hatch, say 2 ft by 3 ft. That's 864 sq. in. If there was a pressure difference of 1 lb per sq. in. then there would be 864 lbs of force holding the hatch close. If the spaceship had a full atmosphere of 14 lbs. per sq. in. there would 6.048 tons of force holding it close.

There's no guarantee that a specific side will have lower pressure, and a swinging door could suddenly find itself being popped open by a ventilator malfunction on one side. Which is why all airlocks will be sliding doors, not swinging ones.

[shawnhcorey]

Originally Posted by ectropy

There's no guarantee that a specific side will have lower pressure, and a swinging door could suddenly find itself being popped open by a ventilator malfunction on one side. Which is why all airlocks will be sliding doors, not swinging ones.

Sliding doors are harder to seal. Also, they use swinging hatches on submarines to seal off a compartment if there's flooding and those hatches have to withstand more than one atmosphere.

[Dangerious P. Cats]

It's common in fiction to use decompression to suck things out airlocks into space, obviously in a less-realistic settings this would be fine to replicate but I'm wondeirng if it could be done in a more realistic setting.

[Crakkerjakk]

Originally Posted by Trachmyr

In every space campaign I've run, uniforms are in fact Mechanical Counterpressure Suits, and evryone usually carries a small inflatable helmet with a 3 minute + scrubber air supply in a caro pocket.

Same. This also explains why in the future everyone is always traipsing around in spandex bodysuits. I treat the suits as basically long underwear everyone is always wearing, with most people wearing something light with lots of pockets on top of it for modesty.